An exhaust gas purification control device is known in which a plurality of catalysts are arranged in series in an exhaust passage and an air-fuel (A/F) ratio is controlled while detecting the status of an upstream side catalyst and a downstream side catalyst, wherein, when the oxygen adsorption amount of respective catalysts becomes excessive during a fuel-cut operation for example, the rich degree or the degree in richness of the air-fuel ratio will be changed based on the detection values across the downstream catalyst (Patent Document 1).